The invention relates to a method for connecting two flat laminated cable ends.
In motor vehicle construction, so-called flat laminated cables or FLCs are used with increasing frequency. As used herein, and as understood internationally, flat laminated cables are flat cables in which a multiplicity of parallel film-like conductor tracks are arranged between two insulating plastic laminates.
JP 07326404 A (Patent Abstracts of Japan (CD-ROM), Vol. 95, No. 12) proposes connecting flat laminated cables by incorporating electrically conducting powder in the plastic laminate at the cable ends. For connection, the flat laminated cables are laid exactly one on top of the other at their ends, so that the conductor tracks of one cable come to lie over the conductor tracks of the other cable. The cable ends are then pressed onto each other and heated, so that the plastic laminate over the conductor tracks melts locally and the incorporated metal powder establishes the electrical contact between the assigned conductor tracks.
In JP 11149951 A (Patent Abstracts of Japan 1999), it is proposed to prefabricate the ends of flat laminated cables to make it possible for two flat laminated cables to be connected. The flat laminated cable ends are stripped of insulation on one side, so that the conductor tracks protrude bare from the film substrates. Moreover, the conductor tracks are angled away at the ends of the flat laminated cable approximately by an angle of 45xc2x0 with respect to the longitudinal direction of the flat laminated cable. As a result, when the stripped sides of two flat laminated cable ends are laid one on top of the other, the conductor tracks of the first flat laminated cable cross over the conductor tracks of the second flat laminated cable. By virtue of the crossing of the conductor tracks, the two flat laminated cables do not have to be aligned exactly flush to allow the conductor tracks to be connected to one another.
For cabling electrical devices in motor vehicles, these methods of connection are suitable only if the length of the flat laminated cable is prefabricated; if it must shortened even slightly, or if a longer flat laminated cable is required, the ends of the flat laminated cables can no longer be connected by the methods described above.
One object of the invention is to provide a method of connecting two flat laminated cables in which flat laminated cables as roll stock can be used, and the ends of the flat laminated cables can be connected without being prefabricated.
This and other objects and advantages are achieved according to the invention by placing a metal strip, tin-plated with a solder coating, transversely over the conductor tracks between the two flat laminated cable ends, pressing the flat laminated cable ends onto each other with the tin-plated metal strip lying in between, applying current to the metal strip and heating it until the solder of the metal strip melts and enters into a soldered connection with the conductor tracks of the flat laminated cables. After the soldered connection, the metal strip is separated or severed in the intermediate spaces between neighboring conductor tracks.
The advantage of this method is that it provides a simple and reliable way to make a proven soldered connection of the conductor tracks to one another. Soldered connections, particularly soft-soldered connections, can be reliably and permanently produced even at temperatures below 230xc2x0 C. Since the heat transmission from the tin-plated metal strip to the conductor tracks is especially great at the point at which it rests on them, the flat laminated cable is locally heated, as desired, particularly at the location of the conductor tracks to be connected. Therefore, melting of the plastic laminate over a large surface area does not take place and the insulating and protecting function of the plastic laminate is preserved even in the connecting region of the two flat laminated cable ends.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.